A vacuum-formed tray, an embossed carrier tape or the like obtained by thermally forming a sheet is used as a packaging container for intermediate products for many industrial products such as electronic equipments or automobiles. And, as a sheet for a packaging container for ICs disfavoring static electricity or various components having ICs, a sheet having a polystyrene resin containing a conductive filler such as carbon black laminated on a substrate layer made of a polystyrene resin or an ABS resin, is used (e.g. Patent Documents 1 to 3). However, there has been drawbacks such that the rigidity is inadequate when a polystyrene resin is used for the substrate layer, and on the other hand, when an ABS resin is used, no adequate shaping property is obtainable at the time of forming the sheet into various containers by e.g. vacuum forming, and further when a polystyrene resin and an ABS resin are used in combination for the substrate layer, the difference in physical properties between the machine and transverse directions of the sheet tends to be large, and the mechanical properties in the transverse direction tend to substantially deteriorate.
Patent Document 1: JP-A-9-76422
Patent Document 2: JP-A-9-76425
Patent Document 3: JP-A-9-174769